<!DOCTYPE html>
<html>
<head>
    <meta charset="UTF-8">
    <title>Document</title>
    <style>
        
    </style>
</head>
<body>
    
</body>
<script>

    // var arr1 = [4,5,6,7];
    // var arr2 = new Array(4,5,6,7);
    // var arr3 = [];
    // var arr4 = arr1;
    // console.log(arr1);
    // console.log(arr2);
    // console.log(arr1 === arr2);
    // console.log(arr1 === arr3);
    // console.log(arr1 === arr4);

    // var arr5 = [4];
    // var arr6 = new Array(4);
    // console.log(arr5);
    // console.log(arr5[0]);
    // console.log(arr5.length);
    // console.log(arr6);
    // console.log(arr6[0]);
    // console.log(arr6.length);


</script>
</html>